Thin film semiconductor chips are known, for example, from U.S. Pat. No. 6,111,272. To produce thin film semiconductor chips of this type, an active layer sequence suitable for emitting photons is grown on a growth substrate. Since the growth substrate generally absorbs some of the photons generated by the active layer sequence, to increase the light yield, the active layer sequence is separated from the growth substrate and applied to a different carrier. There is a reflective layer between the carrier and the active layer sequence. The active layer sequence is joined to the carrier by adhesive bonding or soldering. It is customary to use rigid carriers, such as gallium arsenide or germanium wafers. However, these rigid carriers have the drawback that the thickness of the carrier cannot be reduced to any desired extent, on account of the risk of fracture. In particular, it is difficult to realize carrier thicknesses of less than 100 μm by conventional processes. This represents an obstacle to limiting the overall thickness of thin film semiconductor chips.
A further drawback of the known thin film semiconductor chips is that it is difficult to manage the transfer of the active layer sequence from the growth substrate to the carrier body.
To alleviate this problem, it has been proposed in published US patent application no. 2004/0099873 to apply a reinforcing layer and an auxiliary carrier layer to the back surface of the contact material layers. The reinforcing layer and auxiliary carrying layer replace the mechanical carrier used in conventional methods and allow simplified handling of the active layer sequence. However, with this method it is impossible or only possible with great difficulty to test the function of all subsequent thin film semiconductor chips at wafer level following the transfer of the active layer sequence to the auxiliary carrier.